This invention relates to fluid-operated, reciprocating pumps, and especially to double-diaphragm-type pumps that utilize a reversing valve to control the reciprocating, pumping action. More particularly, the invention relates to the operation of a pilot valve for controlling the reversing valve.
This invention also relates to the inventions of my copending U.S. patent application Ser. No. 415,474, filed Sept. 7, 1982, and the disclosure thereof is incorporated by reference herein and made a part hereof.
Fluid-operated pumps, such as diaphragm pumps, are widely used particularly for pumping liquids, solutions, viscous materials, and slurries or suspensions. The word "liquid" as used herein is intended to include all such materials. Typical diaphragm pumps of this general type are shown in my earlier U.S. patents listed below:
U.S. Pat. No. 3,304,126 PA1 U.S. Pat. No. 3,782,863 PA1 U.S. Pat. No. 3,514,227 PA1 U.S. Pat. No. 3,814,548 PA1 U.S. Pat. No. 3,741,689 PA1 U.S. Pat. No. 3,860,034 PA1 U.S. Pat. No. 3,741,692 PA1 U.S. Pat. No. 2,625,886 PA1 U.S. Pat. No. 3,652,187 PA1 U.S. Pat. No. 2,679,209 PA1 U.S. Pat. No. 3,791,768 PA1 U.S. Pat. No. 2,780,177 PA1 U.S. Pat. No. 3,838,946 PA1 U.S. Pat. No. 3,192,865 PA1 U.S. Pat. No. 4,019,838 PA1 U.S. Pat. No. 3,338,171 PA1 U.S. Pat. No. 4,123,204 PA1 U.S. Pat. No. 3,548,716 PA1 U.S. Pat. No. 4,172,698
Other double-diaphragm pumps are shown in the patents listed below:
Double-diaphragm pumps of the type disclosed in the above-listed prior art patents are well known for their utility in pumping thickened or solids-laden liquids, as well as for pumping plain water, other liquids, and low-viscosity solutions based on such liquids. Accordingly, double-diaphragm pumps have found extensive use in pumping out sumps, shafts, and pits, and generally in handling a great variety of slurries, sludges, and waste-laden liquids. Pneumatically-driven diaphragm pumps offer certain further advantages in convenience, effectiveness, portability, and safety. In pumps of this type, the cylindrical casing of the pump is normally mounted in a substantially horizontal position, the diaphragms are disposed vertically, the connecting rod between them moves back and forth in a substantially horizontal direction, both diaphragms communicate with intake and discharge ports, and the air exhaust line vents to atmosphere. Double-diaphragm pumps are rugged and compact and, to gain maximum flexibility, are often served by a single intake line and deliver liquid through a short manifold to a single discharge line.
While most double-diaphragm pumps of the prior art are operated pneumatically, others are hydraulically operated where the circumstances are suitable. The capability for operating such pumps with other than air pressure is highly desirable, such as where suitable compressors are not available. One very simple source of operating fluid is the water obtainable from a local water utility line where the pressure head is normally between 60 and 100 feet. In many situations, the water at line pressure can be readily used and the exhausted water collected and used locally for various purposes.